1. Field of the Invention
The present invention relates to a display device, and more particularly, to an organic light emitting diode display and driving method thereof.
2. Discussion of the Related Art
Conventionally, an organic light emitting diode (OLED) display is a device in which lights are emitted by exciting phosphorus organic compounds, and represents images by voltage-programming or current-programming n×m number of organic emission pixels. The organic emission pixels include an anode, an organic thin film layer, and a cathode. The organic thin film layer has a multi-layer formation that includes an emitting layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) for the purpose of balancing electrons and holes, and increasing the emission factor. In addition, the organic thin film layer includes an electron injecting layer (EIL) and a hole injecting layer (HIL).
The organic emission pixels can be driven by a passive matrix method or an active matrix method. The active matrix method uses thin film transistors (TFTs) to drive the organic emission pixels. In the passive matrix method, an anode and a cathode are formed to cross (or to cross over) each other, and a line is selected in order to drive an organic emission pixel. By contrast, in the active matrix method, a TFT is coupled to an indium tin oxide (ITO) pixel electrode (or an anode), and an organic emission pixel operates according to a voltage maintained by the capacitance of a capacitor coupled to a gate of the TFT. The active matrix method can be further divided into a voltage programming method and a current programming method according to a signal which is applied in order to program a voltage to the capacitor.
The organic EL display requires a scan driver for driving a scan line and a data driver for driving a data line. Output terminals corresponding to the number of data lines are required because the data driver converts digital signals to analog signals and applies them to the data lines. However, the data driver conventionally includes a plurality of integrated circuits, the number of output terminals of the integrated circuits is limited, and therefore many integrated circuits have to be problematically used for the purpose of driving the data lines.
Also, it has been problematic that aperture efficiency of pixels is reduced because the conventional organic EL display must include driving circuits for driving the pixels and the data lines for respective red, green, and blue pixels in a limited display area.